Near the end of his long, illustrious life, about a month shy of his 105th birthday, the distinguished cultural historian and public intellectual Jacques Barzun no doubt had many things on his mind. One was completing a questionnaire about word usage.

As with so many things, Barzun had fierce opinions about language: He began inveighing against the dangers of sloppy verbiage in the 1940s and never let up. In 1964, he was named to the usage panel of the newly announced American Heritage Dictionary. This September, the dictionary editors sent a special questionnaire to Barzun, their oldest surviving panelist.

In October, when it was announced that Barzun had died, the American Heritage editors figured they would never get the questionnaire back. But his daughter found it on his desk, in a pile of unfinished business, and sent it in. He had completed all but two questions, with terse responses in a shaky hand. The questionnaire reveals a language curmudgeon fiercely protecting the clarity of English well past becoming a centenarian.

“Do you use an online dictionary or a print dictionary?” he was asked. “Print,” he said. (No surprise there.) “Who (if anyone) has had the most influence in developing your sense of what constitutes acceptable English usage?” “Fowler,” he replied, referring to Henry Fowler, whose Dictionary of Modern English Usage was first published in 1926.

“Is there any grammatical construction or word usage that you find particularly annoying?” He responded lucidly, “‘Make sense’ to mean ‘true, correct, acceptable’—anything has to make sense if it is to be proved false or wrong.”

His role as a usage panelist, he wrote, was “to hold back the urge (general, not mine) to make all constructions valid.” And asked if he had ever changed his mind about any points of usage, or if there were any usages he considered wrong but used anyway, he simply answered, “None.”

The questionnaire is a time capsule of sorts, a reminder of the central role that Barzun played in the 20th-century American conversation about English. But it also speaks to how far that conversation has progressed. In some ways, his death marks the passing of a classically informed view of language as a barometer of human nature, and the last bulwark against its decline. “Words are not simply the casual containers and carriers of thoughts and feeling, but their incarnation,” he once wrote.

As regime and dynasty worked their way into everyday political usage, Barzun held the line: “These are technical terms, you blasted non-historians!” he wrote.

Barzun had always held a firm line against what he saw as the misuse of English, though it was his second language: He moved to the United States from France at the age of 12. He attended Columbia University, received his PhD in history there, and then taught at Columbia until his retirement, designing the school’s Great Books curriculum.

While he was primarily known for his sweeping cultural histories, including the best-selling “From Dawn to Decadence,” Barzun also saw it as his mission to sound the alarm about linguistic degradation. In a 1946 review of the supplement to H.L. Mencken’s “The American Language,” Barzun shared Mencken’s delight in the creativity of American English, but sought “a standard by which we can pick and choose among the inventions of a verbally exuberant people.”

In his early writings, Barzun did not rail against such colloquialisms as “ain’t.” Rather, he saw the greatest threat to English coming from the top: the educated classes who “circulate the prevailing mixture of jargon, cant, vogue words, and loose syntax that passes for prose,” as he wrote in a 1953 manifesto for The Atlantic, “English as She’s Not Taught.” Among the jargony terms that most offended him were “sinful hybrids” like “electrocute” and “triphibian,” “misunderstood phrases” like “personal equation” or “psychological moment,” and such noun-to-verb transfers as “contact,” “funnel,” and “process.”

In 1948, when Merriam-Webster was seeking suggestions for the editor of their unabridged dictionary’s third edition, Barzun’s name came up—though, as David Skinner writes in “The Story of Ain’t,” a fascinating new book on the making of Webster’s Third, he was never seriously considered. The job instead went to Philip Gove, whose view of the descriptive role of dictionaries, informed by formal linguistics, stood in stark contrast to Barzun’s stern prescriptivism.

When Webster’s Third was published in 1961, it marked what David Foster Wallace called “the Fort Sumter of the contemporary Usage Wars,” pitting traditionalists against what they saw as grave assaults from permissive modern lexicographers. In the flurry of outrage over the dictionary’s perceived liberalness, Barzun was front and center, going so far as to call the dictionary “the longest political pamphlet ever put together by a party,” embodying “a dogma that far transcends the limits of lexicography.” Barzun even decried the space-saving “swung dash” symbol ~ , used to replace repetitions of a headword, as “a subtle attack on The Word.”

A few years later, in 1964, the American Heritage Dictionary was conceived as something of an antidote to the nonjudgmental Webster’s Third—so it was no surprise that Barzun was enlisted for the first usage panel. The panelists made their opinions known through annual surveys on disputed points of language use. His fellow panelist William Zinsser, the great writer about the art of writing, described some of the survey questions in a piece for Life magazine in 1969, when the first edition of American Heritage was published. (Zinsser, 90, is now the sole survivor of that first panel.) While most of the panelists approved of the general political use of regime or dynasty (as in “the Truman regime”), Barzun held the line: “These are technical terms, you blasted non-historians!”

In later years, Barzun’s views on usage continued to be heard through his friend William Safire, who wrote the “On Language” column for The New York Times until his death in 2009. In the early 1990s, Safire named Barzun to his “On Language Board of Octogenarian Mentors,” along with Alistair Cooke, Dictionary of American Regional English editor Fred Cassidy, and etymologist Allen Walker Read. (Safire himself was in his 60s at the time.) Barzun frequently corresponded with Safire, taking him to task for being too accepting of what he thought were semantic deviations, such as the shift in the meaning of jejune from “insipid” to “childish” (possibly influenced by the unrelated French word jeune, meaning “young”).

Language moves on: All the major dictionaries, American Heritage included, now recognize the “childish” sense of jejune, even if it was rooted in error. In retrospect, this and other usage complaints from Barzun may seem like quixotic carping. But with his passing we have lost a fervid voice for maintaining the clarity of English in the face of onslaughts from technology and commercialism. In his hopes for a plainer, more sensible discourse, Barzun was never jejune—in any sense of the word.

Ben Zimmer is the executive producer of VisualThesaurus.com and Vocabulary.com. He can be reached at benzimmer.com/contact.